Conservative MP Jason Kenney was berated by dozens of his Calgary constituents angry over Ottawa's new tax on income trusts during a town hall meeting on Saturday.

Police watched over the crowd while plain-clothed officers sat amongst the attendees.

People pressed Kenney over the federal government's flip-flop on income trust taxation by constituents worried about what kind of effect such a tax could have on the economic future of the country.

During his election campaign, Prime Minister Stephen Harper made the promise that if elected he would not propose new taxes for income trusts.

Many who showed up for the Calgary meeting had lost substantial amounts from their retirement savings.

"You lost the trust of Canadians, Albertans, Calgarians and worst yet, your constituents," one man said during the meeting.

"This government was elected to bring clarity to parliament and honesty.  We are really getting nothing but lies and more hidden agendas," another fired at Kennedy.

Kenney responded by defending the new tax: "It was a difficult decision and it wasn't taken lightly. But there is a clear rational in the national interest to ensure corporations pay their fair share."

Many in the audience pledged they would never vote Conservative again as a result of the new tax.

"Lies and lies and lies. The whole government, your prime minister is a liar and I think people are getting tired of this," another attendee said.

Kenney responded after the meeting by saying sometimes promises have to be broken.

"We are doing our level best to keep all of your election commitments even though we are in a minority. From time to time, things change and governments have to change with the circumstance and that was the case here," Kenney said.

The Canadian Association of Income Trust Investors said it would continue to press MP's at meetings like this in an effort to prevent the Conservative's Tax Fairness Plan from being voted into law.

The coalition have begun an aggressive marketing campaign in order to make income trusts a key issue in any upcoming federal election.

Income trusts are businesses that pay little or no corporate tax. Instead, corporations that convert to trusts pay most of their cash flows to investors in monthly distributions, who in turn pay taxes on this income.

On Halloween, Finance Minister Jim Flaherty announced the Tax Fairness Plan, which would create a new tax on the money distributed to shareholders by newly formed income trusts, which would shift the tax burden to investors.

Alberta's oil patch is perhaps the industry that will suffer the most from the change to Canada's taxation laws.

With a report from CTV Calgary's Kevin Green and files from The Canadian Press